FORMALDEHYDE 637 the arteries, flushing of the face, and a sense of fullness about the head. In toxic doses amyl nitrite converts hemoglobin into methsemoglobm, renders the blood chocolate- coloured and thereby interferes with the oxygenating function of the red blood cor- puscles. A teaspoonful taken internally has caused poisonous symptoms. A retired medical man suffering from anginoid pain inhaled nine amyl nitrite capsules in less than an hour, and suffered from very severe symptoms, but eventually recovered.10 Cadwallader17 reports a case in which the inhalation of half-an-ounce of amyl nitrite proved fatal. Treatment.—Wash out the stomach. Inject adrenaline or ephedrine hypodermically. Start artificial respiration, if necessary, and give oxygen inhalation with or without carbon dioxide. Post-mortem Appearances.—If administered quickly, the lungs and other organs are found blanched and free from blood. The right chamber of the heart is gorged with blood and the left empty. The brain is pale. If administered slowly, the brain is con- gested and both the chambers of the heart contain blood. Test.—Heated with caustic potash, amyl nitrite forms amyl alcohol and potassium nitrite. Medico-Legal Points,—Poisoning by amyl nitrite is mostly accidental, and rarely suicidal. Amyl nitrite taken by the mouth is much less active than when inhaled, as the nitrous acid which is set' free by the gastric juice is immediately decomposed. After absorption in the blood amyl nitrite undergoes partial oxidation, and appears in the urine as nitrates and nitrites of flie alkalies. METACETALDEHYDE (METALDEHYDE), (C-HiO)! This is prepared by the condensation of acetylene and water by the catalytic action of acid and salts of mercury. It is a white, crystalline compound, insoluble in water and most organic solvents. It is non-volatile and non-explosive at the ordinary tem- perature. It burns without smoke and without leaving any ash, when a flame is applied to it. It is extensively used as a substitute for methylated spirit as a source of heat for lamps and stoves, and is supplied in the form of white elongated tablets under the trade name of "meta fuel". A tablet is usually about 2 inches long and | inch thinck, and weighs, on an average, a little above 4.4 grammes or nearly 70 grains. When taken internally, metacetaldehyde is absorbed slowly from the intestine, and acts locally on the gastro-intestinal tract and remotely on the central nervous system. Symptoms,—The symptoms appear soon after the poison is taken, or they may be delayed for two or more hours. These are nausea, vomiting, pain in the abdomen, rise of temperature even upto 104° or 105 °F., convulsions, cyanosis, stupor, coma and death. Albuminuria is usually a common symptom. Fatal Dose.—The minimum fatal dose for an adult is not known, but two tablets 18 of meta fuel have caused toxic symptoms and six tablets10 have proved fataL Fatal Period.—Death may occur in from twelve to thirty-six hours, or it may be delayed for three or four days, Treatment.—Wash out the stomach with a solution containing sodium bicarbonate, and give a saline purgative. Give hypodermically cardiac stimulants. Inject intra- venously sodium diphosphate and glucose together with insulin subcutaneously. Ad- minister oxygen by inhalation and start artificial respiration, if necessary, Treat convulsions by potassium bromide and chloral hydrate. Post-mortem Appearances.—Signs of irritation in, the stomach and the small intes- tine, The white particles of meta fuel may be present in the stomach contents. The liver shows fatty degeneration. The kidneys show cloudy swelling. The brain and its meninges are hyperaemic. Medico-Legal Points.—Accidental cases of poisoning occur in children, as they occasionally eat meta fuel tablets in mistake for sweets. Suicidal cases of poisoning occur in adults. FOBMALDEHYDE, H.CHO This is formed when methyl alcohol vapour and air are passed over a red hot spiral of platinum wire. It is a colourless gas, possessing a strong pungent odour. It is soluble in water, a 37 to 41 per cent solution being a pharmacopoeia! preparation, Liquor 16. Walter Broadbent, Brit. Med. X, Nov. 3, 1923, p. Sit 17. Medical Record, 1896, 50, p. 816. 18. Samml u. Vergiftungsf., 1936, 1, 73 ; Med. Annual, 1940, p. 460, 19. Lancet, July 22, 1933, p. 194.